Mercedes

Have Mercedes questions? Ask a mechanic for answers ASAP

Ask an Expert,
Get an Answer ASAP!

Fuel pressure is low, only 45, 200k, mlJA: Are you fixing…

Customer Question
Fuel pressure is low...

Fuel pressure is low, only 45

Mechanic's Assistant: How many miles are on the vehicle? And when was it last serviced?

200k

Mechanic's Assistant: What is the model/year of your Mercedes?

Ml(###) ###-####

Mechanic's Assistant: Are you fixing your 430 yourself? What have you tried so far?

Yes, I have tried by pass relay and I could here the fule pump run when it is turn on

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

I belive the relay is good and the voltage is good also

Submitted: 11 months ago.Category: Mercedes
Show More
Show Less
Ask Your Own Mercedes Question
Answered in 23 minutes by:
7/29/2017
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago
David Craig
David Craig, Auto Mechanic
Category: Mercedes
Satisfied Customers: 5,798
Experience: Owner/Mechanic at 3D Automotive
Verified

Hi Im David, thanks for visiting the site. you need to replace the filter and if that doesnt do it then your fuel pump is weak, replace it. thats way low.

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
sorry the information that I put in was wrong, the actual pressure is 55 and the engine shout off after warm up
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

ok, 55 is good. how long did it run before shutting off?

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
about 30 minut on ideal
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

ok, did you try to start it right back up?

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
it not start. it crank but not fire up
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

then it starts when cooled down correct?

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
it took a while to cool down enough
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

classic crankshaft position sensor thermal breakdown

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
how could i confirm this? is there any way to test it?
Customer reply replied 11 months ago
I mean I don't even know where it is located. I would like to confirm it before tare everything in parts.
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

sure give me a few to find the test

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
thanks
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

heres the location. it sits on top of the transmission where the tranny and engine meet. leave the connector on and back probe the connector while the engine is being cranked and check that it produces ac voltage

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
thanks, ***** ***** it control ? fuel injector or spark plug or both?
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

it controls rotation information to the computer to let the computer know the engine is rotating then the computer will command the injectors to pulse and the coils to fire

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
whiche means the injector will not release fuel when the crankshaft position sensor bad?
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

yes or when its overheated.

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
but what could possibly cost it overheated?
Customer reply replied 11 months ago
looks like the most important is to find out the cause of the overheat.
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

age, heat,

Ask Your Own Mercedes Question
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

no thats not the most important thing, ignition components are subject to a lot of heat and over the years they start breaking down

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
it would be OK if I put a new one ?
Customer reply replied 11 months ago
I am worry about it may fail again if I could not remove the cause of the overheat
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

sure, replace it.

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
would you also provide me the correct fuel pressure for this kind of car and how could I know which part cause the problem? fuel pump or regulater?
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

I thought you said the pressure was 55 which is good

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
would crankshaft position sensor controls fuel injector only or spark plug also?
I am trying to find a way to confirm that the position sensor is the problem
Customer reply replied 11 months ago
the fuel pressure is 55 for a while and I also noticed that the pressure could be very low sometimes
Customer reply replied 11 months ago
I have noticed that the fuel pressure kind of very low while the engine was cranking but not fire up
Mercedes Mechanic: David Craig, Auto Mechanic replied 11 months ago

ok, you are overthinking things, here. I will open this up o maybe someone else can explain it to you better. good luck

Ask Your Own Mercedes Question
Mercedes Mechanic: Wolfgang, Mercedes Technician replied 11 months ago
Wolfgang
Wolfgang, Mercedes Technician
Category: Mercedes
Satisfied Customers: 5,219
Experience: master tech benz ase cerified L1 and L2
Verified

Thanks for choosing Just Answer . I'm Wolfgang here to help!!

I am confident we can resolve your problem together. Please
understand that I don't know your skill level. In most cases when you have a problem
with the way the vehicle performs, specialized tooling is required to acquire computer
data/information or engine testing results. We didn’t build these complicated vehicles; we
just diagnose and fix them. Also understand that I can't see, smell, hear, or touch the
vehicle either, so it may take a few replies to get to satisfactory results. Note there may be an issue where the complexity of the issue will require a Premium Service. This service will be an addition to the normal question cost. Usually it does not come down to this but keep in mind!! I am also going to direct you with the fastest, easiest and most common things to check first. Please be
patient and permit me to do what I do best.
I also try to give all of the information you may need, expecting a “positive rating” in
return. I will also continue assisting you after you have rated me, if necessary. If there
is any reason I cannot get a positive rating, please let me know why “in advance”, so I
can go another direction for you. I am sorry you’re having this problem; I’ll help you
through it.
Below is my first answer or request for more information. If you do not understand it, or you need more information from me, or need me to go in more detail.

I do need the vin # to get the factory repair information to assist!!

Thanks

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
1st thing that I need to know is the resistance reading of the fuel pump at the point the relay. I would do a few test today with complete report and contact you later. please let me know if you would like do some test for you to have a batter understanding, I would perform the test and give you the result today.
Mercedes Mechanic: Wolfgang, Mercedes Technician replied 11 months ago

the resistance reading would vary on electromechanical motors.

what is the exact issue of the vehicle? no start ? scan test performed?

thanks

Ask Your Own Mercedes Question
Customer reply replied 11 months ago
Where could I buy the scanner
Does it have one could attach to I phone?
Mercedes Mechanic: Wolfgang, Mercedes Technician replied 11 months ago

As i have asked what is the exact issue with the vehicle please.

If you can help me with what is going on i can help you in fixing.

Thanks

Ask Your Own Mercedes Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a mercedes mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask MB Paul Your Own Question
MB Paul
MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3,567
3,567 Satisfied Customers
Experience: Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes

MB Paul is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible.

CharlesWalnut Creek, CA

As a single woman, I really appreciate an excellent and affordable opinion.
Thank you Geordie, I will not hesitate to contact justanswer in the future!

SueCharleston, WV

Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff.

JimCastleberry, FL

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

< Previous | Next >

Meet the Experts:

MB Paul

MB Paul

Mercedes Technician

3,567 satisfied customers

Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes

Marty

Marty

Mercedes Technician

29,460 satisfied customers

Bosch Certified Master Tech. Over 35 years experience.

Lou P. master tech

Lou P. master tech

Mercedes Technician

4,460 satisfied customers

20 years Master Certified excellent fix rate and have access to factory wiring, and instructions.

Michael Warfield

Michael Warfield

Factory Mercedes-Benz Technician

3,132 satisfied customers

Mercedes-Benz Master Certified technician

Matt

Matt

Engineer

643 satisfied customers

Mechanical Engineer with 23 years experience in the auto industry, 8 yrs in formula 1 engine testing

promerc

promerc

mercedes diagnostic technician

553 satisfied customers

Qualified mercedes diagnostic technician & service team manager , ATA registered Master tech

Hipo64

Hipo64

Mercedes Technician

444 satisfied customers

Work and diagnose electronics on daily basis.

< Previous | Next >

Related Mercedes Questions
I made a mistake, I've been having plugged dpf problems with
Ok, I made a mistake, I've been having plugged dpf problems with my 2010 Mercedes-Benz ML350, got fed up and pulled the ecm / cdi and sent it away to do the dpf add blue delete with JR performance chi… read more
Lou P. master tech
Lou P. master tech
Mercedes Technician
Bachelor's Degree
4,460 satisfied customers
Vechicle is hard starting, try first time turns over, but
vechicle is hard starting, try first time turns over, but will not start, 2nd time it will start … read more
Matt
Matt
Engineer
Bachelor's Degree
643 satisfied customers
Loss of power when its warmed up, ML 270 cdi year 2003,
Loss of power when its warmed up JA: What is the model/year of your Mercedes? Customer: ML 270 cdi year 2003 JA: Are you fixing your vehicle yourself? What have you tried so far? Customer: Nothing JA:… read more
Matt
Matt
Engineer
Bachelor's Degree
643 satisfied customers
Starts right up bet then dies right away fuel pressure is
Starts right up bet then dies right away fuel pressure is good checked with a guage 45 to 50 psi one thing I did do cuz it's been running good I just put in an aftermarket stereo … read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
ML 350: Sir, I am in México and I have a MB 2006 ML 350, its
Sir, I am in México and I have a MB 2006 ML 350, its VIN is 4JGBB86E76A085616, it does not start, it looks like the fuel pump does not work, we had replaced the fuse number 30 with 5 amps… read more
Lou P. master tech
Lou P. master tech
Mercedes Technician
Bachelor's Degree
4,460 satisfied customers
Mercedes ML. 320: 2003 Mercedes ML 320. Driving on freeway
2003 Mercedes ML 320. Driving on freeway and engine starting losing power. No acceleration when stepping on gas. Pulled over, turned car off, restarted but ran rough, popping sound from under car, sta… read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
Mercedes-Benz ml 350: 2003 350 ml benz starts than stalls led,
2003 350 ml benz starts than stalls led, on sterio is recognizings keys, seems to be fair pressure in fuel rail did not use a psi guage… read more
Matt
Matt
Engineer
Bachelor's Degree
643 satisfied customers
Mercedes-Benz 300 TE wagon reg Mercedes 300 TE wagon regular problem;low
Mercedes 300 TE wagon regular problem;low fuel pump pressure tested visual : disconnected fuel line into fule inj. dist body.....set into bottle....turn IG to on.........easy going pressure flow......… read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
2001 mercedes: stopped running..engine turns..I saw no voltage drop
I have a 2001 Mercedes ML 55, which suddenly stopped running. The engine turns over well and I saw no voltage drop off on the battery when I checked it as the engine was being turned over. Please prov… read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
MY MERC ML 270 CDI W163 WILL TURN OVER BUT WILL NOT START ,BUT..BUMP
MY MERC ML 270 CDI W163 WILL TURN OVER BUT WILL NOT START ,BUT YOU BUMP START IT IT RUNS LIKE A DREAM (HELP) STUART… read more
MB Paul
MB Paul
Mercedes Technician
Vocational, Technical or Trade Scho
3,567 satisfied customers
2001 ML320: it cranks but doe not start..Position Sensor
I have a 2001 ML320 and it cranks but doe not start. Everything I have read says to replace the Cranshaft Position Sensor. It that true? Also what is the best way to get to it?… read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
1998 ml320: stop light..accelerate shut..check engine light
I have a 1998 ml 320 and it shut off at a stop light than i turned on and it would not accelerate shut off again and it is okey, i due not get a check engine light. This happen a couple of times. But … read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
2000 Mercedes-Benz Ml320: an intermittant problem..fuel delivery
I have a 2000 Mercedes-Benz Ml320. It has developed an intermittant problem in that when starting it will turn over but not fire up. This would suggest some type of fuel delivery problem-I believe. Th… read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
1999 ml320: wont start..the car started and ran..drove..mile
My 1999 ML 320 wont start. Yesterday I changed the CPS but the car started and ran after changing it. Today I drove down the street about 1/4 mile and stopped at a house. After chatting for 40 minutes… read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
ML320: fuel pump..psi..Amps start at 5 then drop..low pressure
ML320 fuel pump only producing 20 psi. Amps start at 5 then drop to 3. Is pump relacement going to solve this or is there another reason for the low pressure and low current draw?… read more
Stan
Stan
Technical support engineer
Bachelor\u0027s Degree
106 satisfied customers
My 99 mercedes ML 430 all of the sudden with no prior problems
My 99 mercedes ML 430 all of the sudden with no prior problems just wont start. It turns over and over but will not start. fuel pump relay and fuse are good as is the fuel injector fuse. I hear the fu… read more
Rob
Rob
Diagnostic Technician
High School or GED
196 satisfied customers
98 Mercedes ML320: 110000 km, I..problems starting..car every..weather
I have a 98 Mercedes ML320 with 110000 km, I have problems starting the car every morning, especially when the weather is cold. It usually takes 3-4 tries before I can start the car.… read more
Marty
Marty
Mercedes Technician
Associate Degree
29,460 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x